1. Field of the Invention
Wheels for roller skates must be durable, resilient and preferably, inexpensive to manufacture. Typically, a wheel is molded from polyurethane in a single operation, resulting in a wheel that has all of the properties listed above and a wheel that is capable of accepting and supporting bearings without additional components or structures.
Adding the feature of having flashing lights mounted on a wheel will significantly affect its marketability. A wheel with flashing lights must, of course, retain the properties of durability, resilience and particularly, low manufacturing cost, or any marketing advantage will be lost. It has not been possible heretofore to provide a wheel having flashing lights that retains all of these desirable properties.
2. Description of Prior Art
Price, in U.S. Pat. No. 4,298,910, discloses a wheel whereby an electric generator is contained within the wheel. Price's wheel uses a stationary body mounted between the wheel bearings. The mounting of the stationary body creates a problem in that material must be removed in the area between the bearings to make room for the stationary body. The loss of this material requires that additional rigid structures must be added to support the outer bearing race for both the inner and outer bearing assembly. The resultant wheel is a relatively complicated device that requires precision components for supporting the bearings, windings and magnet. Additionally, the "generator" portion of the wheel would presumably require bonding to an outer covering material that would exhibit the resilient properties required for roller skate wheels. The result of these requirements are increased manufacturing costs.
A solution to the problems created by employing an inner stationary body to mount the permanent magnet is to mount the magnet externally to the body of the skate wheel. This has not been possible prior to the present invention for the following reasons:
(a) The windings cannot be mounted close to the surface of the wheel that contacts the surface the wheel moves over, since any wear and tear on this outer surface would expose and damage the windings. Additionally, an external magnet mounted close to this wheel surface might easily jam the wheel when debris or pebbles picked up by the wheel attempted to pass through the necessary gap between the wheel surface and magnet.
(b) A winding mounted near one of the inner or outer wheel surfaces, that is, one of the surfaces that is oriented perpendicular to the axle, would necessarily be small, and not capable of producing enough electrical energy to energize a light emitting means. The diameter of such a winding must necessarily be small to allow the winding to fit between the outer bearing race and the outer radius of the wheel. Increasing the thickness of windings mounted in this position would not solve the problem, since the magnetic reluctance of the windings and the material the wheel is constructed of is high, and therefore the portion of the windings not close to the magnet would move through a weakened magnetic field, generating little electrical energy.